The theory that eating local honey, or pollen, can reduce allergies is based on the proven effectiveness of immunotherapy.

Immunotherapy typically involves shots, or under-the-tongue drops of small amounts of the specific allergens to which a person is allergic. Over time, the concentration continues to increase and the body gradually builds up immunity to these allergens.

Proponents of eating locally produced, unprocessed bee honey, pollen and propolis say that these products can also work as immunotherapy, and reduce seasonal pollen allergies. While this might be true for a small number of locally flowering plants, in general bees aren't collecting pollen from the plants that people are most allergic to.

Weeds, grasses and trees are the leading causes of seasonal allergies. Weeds, grasses and trees produce very small and light-weight pollen that is designed to be distributed by the wind. Because they don't need to attract insect pollinators, they are usually a dull color, without scent, and have small or no petals since no insect needs to land on them.

Plants that are pollinated by insects like bees are typically brightly colored and have a strong scent to attract the animal pollinators. These flowering plants have large, heavy pollen that doesn't travel well in the wind, and which usually aren't a big contributor to seasonal allergies.